Drop detection device

ABSTRACT

A drop detection device having a spherical inertia member disposed within an enclosure. The enclosure has multiple faces, preferably six faces oriented orthogonally, with each face having a pressure contact member. The exertion of a predetermined force by the spherical inertia member on the pressure contact member causes a signal to be activated. Multiple enclosures maybe disposed in different orientations in a housing of a fragile product to provide a signal if the product is dropped in any one of multiple directions.

PRIORITY CLAIM

This application is a 371 of PCT/GB02/03325 filed Jul. 19, 2002 whichclaims the priority of United Kingdom Patent Application No. 0121067.3filed Aug. 31, 2001.

BACKGROUND OF THE INVENTION

1. Technical Field

This invention relates to a drop detection device. In particular, itrelates to a device for use in relation to a product or package that hasa fragility requirement that needs to be monitored. Still moreparticularly, the device detects whether the product or package has beendropped or impacted by another object.

2. Description of the Related Art

Certain materials and devices can be damaged if dropped. For example,dropping or hitting a hard disk drive with sufficient force can resultin components of the hard disk drive being damaged. However, the damagemay not be evident, either by looking at the exterior case of the harddrive, or even by opening up the case and physically examining thedrive's components. Nonetheless, when put into operation, the drive maynot function properly due to being dropped. That is, the external shockcan cause a disk within the disk drive to slip resulting in inaccuratedata recording or increased access times.

To detect whether a device or material has been dropped, differentdevices have been developed in the past. For example, acceleration limitswitches are known in which a spherical inertia body made offerromagnetic material is maintained in a resting position by apermanent magnet. On the opposite side of the spherical body to themagnet a flexible conducting diaphragm is disposed beyond which is aprinted circuit board. If the spherical body is accelerated away fromthe permanent magnet, it will impact the diaphragm, which is flexible,and the diaphragm will deform to contact an element on the printedcircuit board causing some form of signal to be activated.

Acceleration limit switches of this type have the disadvantage that theyare only sensitive to acceleration in a single direction. Other forms ofdrop detection device may include fragile destructive assemblies or hightechnology accelerometers.

What is needed, therefore, is a multi-directional drop detector that isable to detect and provide an indication signal of a drop event that hasbeen inflicted on a hard disk drive or other impact sensitive equipmentor material.

SUMMARY OF THE INVENTION

It is an aim of the present invention to provide a low cost robustassembly that can be used in any product that requires detection ofwhether it has been dropped or impacted by another object. It is afurther aim to provide a drop detection device that detects a drop orimpact in any direction or orientation of the product in which thedevice is provided.

According to a first aspect of the present invention there is provided adrop detection device having a spherical inertia member disposed in anenclosure, the enclosure having a plurality of faces, each face having apressure contact member, wherein a predetermined force exerted by thespherical inertia member on one of the pressure contact members causes asignal to be activated.

Preferably, the pressure contact members are formed of a deformablediaphragm spaced from a contact member, wherein the predetermined forcedeforms the diaphragm to contact the contact member.

The predetermined force may be determined by the mass of the sphericalinertia member. The predetermined force may be determined by theflexibility of the diaphragm and the distance between the diaphragm andthe contact member.

In a rest position or during normal motion, the spherical inertia membermay rest in contact with the contact pressure members on the faces andmay exert a force of less than the predetermined force on the pressurecontact members.

The drop detection device preferably includes first and secondenclosures in the form of cubes, the second enclosure being adjacent andoriented differently to the first enclosure. The provision of two ormore enclosures oriented differently to each other provides coverage ofdrop or impact detection in a wider range of directions approximating to360°.

The enclosure or enclosures may be formed by two molded halves of ahousing.

The spherical inertia member may be calibrated to a predetermined massin relation to the required sensitivity of the drop detection device.

The pressure contact members may use pressure contact keyboard typetechnology.

The signal that is activated is an LED, an audible alarm or other signalmeans. The signal means may be disposed on the outside of a packaging orobject.

The drop detection device may be formed in the molding of a computerproduct. The drop detection device may be a self-contained assembly ormay be molded into packaging for products.

BRIEF DESCRIPTION OF THE DRAWINGS

The novel features believed characteristic of the invention are setforth in the appended claims. The invention itself, however, as well asa preferred mode of use, further purposes and advantages thereof, willbest be understood by reference to the following detailed description ofan illustrative embodiment when read in conjunction with theaccompanying drawings, where:

FIG. 1A is a cross-sectional view of a drop detection device inaccordance with a preferred embodiment of the present invention;

FIG. 1B is a cross-section of a drop detection device in accordance witha preferred embodiment of the present invention;

FIG. 2A is a transparent plan view of a drop detection device inaccordance with a preferred embodiment of the present invention;

FIG. 2B is a transparent side view of the drop detection device of FIG.2A in direction A;

FIG. 2C is a transparent side view of the drop detection device of FIG.2A in direction B;

FIG. 3 is a developed profile of a pressure membrane in accordance witha preferred embodiment of the present invention; and

FIG. 4 is a circuit diagram for use in a drop detection device inaccordance with a preferred embodiment of the present invention.

DETAILED DESCRIPTION OF ILLUSTRATIVE EMBODIMENT(S)

Referring now to FIG. 1A, a drop detection device 100 is provided in amolded housing 102. The molded housing 102 can be formed as part of aproduct or incorporated in packaging in order to be part of or in closeproximity to a fragile object. For example, the drop detection device100 can be formed integrally in a molded cassette of a computer harddrive in a laptop computer in order to detect if the computer has beendropped or impacted in some way.

Alternatively, the molding can form a self-contained drop detection itemfor use as a shipping or packaging monitor, for example, on shippingcontainers.

The molded housing 102 is formed in two halves 104, 106 with a moldsplit line 108. Two cavities 110, 112 are formed with half of eachcavity 110, 112 molded into each of the two halves 104, 106 of themolded housing 102. When the two halves 104, 106 of the molded housing102 are placed together, the cavities 110, 112 are completely enclosedwithin the molded housing 102.

Each of the two cavities 110, 112 is a cubic shape and the two cavities110, 112 are at different orientations to each other. More than twocubic cavities 110, 112 could be provided with further differentorientations.

Each cavity 110, 112 has a membrane 114 or other form of sheet materialpositioned on the internal faces of the cavities 110, 112. The membrane114 has a plurality of sides 116, each side positioned on an internalface of the cubic cavities 110, 112. Each side 116 has a pressure pad118 centrally located on each side 116. In each cubic cavity 110, 112there are six pressure pads 118. The membrane 114 and the pressure pads118 can be formed of a suitable material such as Mylar or polyester.

Each cavity 110, 112 houses a calibrated spherical object 120 of knownmass. In each cavity 110, 112 the spherical object 120 is held inposition centrally within the cavity 110, 112 by contact with thepressure pads 118 on each of the sides 116. The pressure pads 118 aredisposed between the spherical object 120 and the membrane 114 thatlines the cavity 110, 112.

Referring to FIG. 1B, a cross-section of the components in a singlecavity 110 through the center of the cavity 110 is shown. A membrane 114forms a cubic surround that lines a cavity 110 in a molding. Themembrane 114 has six sides 116, with four of the sides 116 shown in thecross-section of FIG. 1B. One side 116 of the membrane has electroniccircuitry mounted on it, in the form of a printed circuit board (notshown), such as a circuit 400 depicted in FIG. 4.

Each of the sides 116 has a pressure pad 118 mounted centrally on theinner surface 122 of the membrane 114. The pressure pads 118 are shownin the later figures as being circular, although the pressure pads 118could be square or any other suitable shape. Each pressure pad 118 ismounted on the inner surface 122 of a side 116 of the membrane 114 onmountings 124 which mount the pressure pad 118 a spaced distance 126from the inner surface 122 of the membrane 114.

The pressure pads 118 are formed of an elastic conductive diaphragm 128which may be a plastic material. A predetermined force x is required todeform the diaphragm 128 sufficiently toward the membrane 114 for thediaphragm 128 of the pressure pad 118 to contact the inner surface 122of the membrane 114. At rest or during normal motion, the sphericalobject 120 contacts the pressure pads 118 but does not deform thediaphragm 128 of the pressure pad 118 sufficiently for the diaphragm 128to contact the inner surface 122 of the membrane 114.

The predetermined force x is dependent on a number of parameters,including the flexibility of the diaphragm 128 which is dependent on itsmaterial and thickness, the spaced distance 126 between the diaphragm128 and the membrane 114, and the mass of the spherical object 120.These parameters can be pre-set to provide a predetermined sensitivityof the drop detection device 100.

Many constructions of suitable pressure pads 118 could be used, allusing the deforming of a surface with a force. For example, keyboardtechnology uses such pressure pads.

The inner surface 122 of each side 116 has a membrane 114 disposedopposite the deformable diaphragm 128 of the pressure pad 118, has acontact component connected to the electronic circuitry disposed on oneof the sides 116. The contact component, when contacted by the deformeddiaphragm 128 of the pressure pad 118, promotes a signal from theelectronic circuitry. The electronic circuitry on the side 116 of themembrane 114 is extended out of the cavity 110 in which the membrane 114is disposed, by means of connectors 130 to a separate electronic circuitfrom which the signal can be emitted. Alternatively, connectors 130 maybe a pair of wires, with one wire attached to membrane 114 and the otherwire attached to inner surface 122, such that contacting membrane 114 toinner surface 122 results in a closing of a switch, such as depicted ascontact pads 408 in FIG. 4 discussed below.

Referring to FIGS. 2A, 2B and 2C, a drop detection device 200 is shownincorporated into a molded cassette 202 of a computer. Two cavities 210,212 are provided of the form shown in FIGS. 1A and 1B. FIG. 2A is a planview of a corner 203 of the molded cassette 202. The molded cassette 202surrounds a data file or a hard disk drive 205. The molded cassette 202has two halves 204, 206, one on top of the other with the mold splitline 208 in a horizontal plane, as seen in FIG. 2B.

The two cavities 210, 212 are formed in the molded cassette 202 near thecorner 203. The first cavity 210 is oriented with its top and bottomfaces of the cube parallel to the mold split line 208. In FIG. 2A, a toppressure pad 218 of the pressure contact membrane 214 is shown in thefirst cavity 210. The second cavity 212 is oriented with an edge of thecube uppermost and two pressure pads 218 are shown in the second cavity212.

A further cavity 226 is provided in the molded cassette 202 housing anelectronic circuit 222, which is driven by a pulse from a contactbetween a pressure pad 218 and a component on the surrounding membrane214.

The contact components on each side of the membranes 214 in each cavity210, 212 are connected to electronic circuitry on one side of a membrane214 in each cavity 210, 212 and the circuitry is extended out to theelectronic circuit 222 in the separate cavity 226 and connected by asolder reflow joint. Where there is more than one cavity 210, 212, theelectronic circuitry in each cavity is connected to the electroniccircuit 222 in the separate cavity 226.

The electronic circuit 222 includes an LED 224 which indicates if one ofthe pressure pads 218 in any one of the cavities 210, 212 has contactedthe contact component on the membrane 214 opposite the pressure pad 218.

FIG. 2B is a side view of the arrangement of FIG. 2A from direction Ashowing the two cavities 210, 212 and the electronic circuit 222 in theadditional cavity 226 in the molded cassette 202. The two cavities 210,212 and the additional cavity 226 for the electronic circuit 222 areformed in the two halves 204, 206 of the cassette molding 202.

FIG. 2C is a side view of the arrangement of FIG. 2A from direction B.This shows the two cavities 210, 212 one in front of the otherillustrating their different orientations in the cassette housing 202.The data file or hard disk drive 205 is surrounded by protective foam228.

Referring to FIG. 3, a developed profile 300 of the membrane 314 isshown. The membrane 314 has six faces 302 corresponding to the sixinternal faces of each of the cubic cavities 110, 112. Each face 302 hasa pressure pad 318, which is circular, and covers as much of each face302 as possible. The membrane 314 has connectors 320 to connect themembrane 314 to the electronic circuit 222 and LED 224. The corners 322of each face 302 are cut away for ease of assembly.

The electronic circuit 222 is shown in more detail in FIG. 4. Thecircuit 400 has a battery 402, a fuse 403, first and second resistors404, 406, contact pads 408, and an LED 410 and a transistor 412. Thecontact pads 408 are the diaphragm 128 of the pressure pad 118 and thecontact component of the membrane 114 shown in FIG. 1B. When the contactpads 408 are open, the current from the battery 402 passes through thefirst resistor 404 and the fuse 403 without blowing the fuse 403. Thecontact pads 408 are closed when a pressure pad 118 of the membrane 114is activated. This causes the fuse 403 to be blown as the current fromthe battery 402 bypasses the first resistor 404.

Once the fuse 403 has been blown, the transistor 412 operates and thebattery 402 powers the LED 410 via the second resistor 406 resulting inan illuminated LED 410. As an alternative arrangement, a flashing LED oran audible alarm could be used in place of the LED.

In practice, a drop detection device 100, 200 as described is providedin a molded housing 102, 202 of a product, such as a computer, or inpackaging surrounding a fragile object. Alternatively, the dropdetection device 100, 200 is provided as a self-contained assembly. Ifthe object is dropped or impacts with another object, the object willaccelerate and/or decelerate very quickly.

Sudden acceleration causes the spherical objects 120, which act asinertia bodies, to exert a force on the pressure pads 118, 218 in theopposite direction to the direction of acceleration. Deceleration causesthe spherical objects 120 in the cavities 110, 112, 210, 212 to exert aforce on the pressure pads 118, 218 of the membrane 114, 214 in thedirection in which the object was traveling before the impact.

When a pressure pad 118, 218 has had a force exerted on it by thespherical object 120 above a predetermined force x, the pressure pad118, 218 is deformed sufficiently to contact the membrane 114 andactivate a switch in an electronic circuit 222 in the molded housing102, 202 which turns an LED 402 to an ON state.

The mass of the calibrated spherical objects 120 can be tuned to givethe required sensitivity by altering the predetermined force x requiredto activate the drop detection device 100, 200 and therefore changingthe specification of protection. As an example, ball bearings could beused as the spherical objects 120.

Due to the different orientations of the two cubic cavities 110, 112,210, 212, impact in a plurality of different directions can be detected.This provides detection of a drop or impact in directions ofapproximately 360°. Two cavities have been illustrated; however, morethan two cubic cavities could be used, for example four cubic cavitiescould be used in different orientations. Also, the cavities do not needto be cubic. Cavities with more than six faces could be used, forexample in the form of octahedrons, etc.

While the invention has been particularly shown and described withreference to a preferred embodiment, it will be understood by thoseskilled in the art that various changes in form and detail may be madetherein without departing from the spirit and scope of the invention.

1. A drop detection device comprising: a spherical inertia memberdisposed within an enclosure, the enclosure having a plurality of faces,each face having a pressure contact member, wherein a predeterminedamount of force exerted by the spherical inertia member on one of thepressure contact members causes a signal to be activated, and whereinthe drop detection device includes a first enclosure and a secondenclosure, the first and second enclosures having cube shapes, thesecond enclosure being adjacent and oriented rotationally offset to thefirst enclosure, wherein the first enclosure has contact pressuremembers for detecting any of a first set of orthogonal forces, and thesecond enclosure has contact pressure members for detecting any of asecond set of orthogonal forces, the first and second sets of orthogonalforces being offset to each other.
 2. The drop detection device of claim1, wherein the pressure contact members are formed of a deformablediaphragm proximal to but not touching a contact member, wherein thepredetermined amount of force deforms the diaphragm to contact thecontact member.
 3. The drop detection device of claim 1, wherein thepredetermined amount of force is determined by a mass of the sphericalinertia member.
 4. The drop detection device of claim 2, wherein thepredetermined amount of force is determined by a flexibility of thedeformable diaphragm and a distance between the deformable diaphragm andthe contact member.
 5. The drop detection device of claim 1, wherein ina rest position or during normal motion, the spherical inertia memberrests in contact with the contact pressure members on the faces exertinga force of less than the predetermined amount of force on the pressurecontact members.
 6. The drop detection device of claim 1, wherein theenclosure is formed by two molded halves of a housing.
 7. The dropdetection device of claim 1, wherein the spherical inertia member iscalibrated to a predetermined mass in relation to the requiredsensitivity of the drop detection device to result in a signal beinggenerated upon a pre-determined drop force being exerted on the dropdetection device.
 8. The drop detection device of claim 1, wherein thepressure contact members are contact keys.
 9. The drop detection deviceof claim 1, wherein the signal activates a visual indicator.
 10. Thedrop detection device of claim 9, wherein the visual indicator is an LED(Light Emitting Diode).
 11. The drop detection device of claim 1,wherein the signal activates an aural indicator.
 12. The drop detectiondevice of claim 11, wherein the aural indicator is an audible alarm. 13.The drop detection device of claim 1, wherein the drop detection deviceis formed during the molding of a computer product.
 14. The dropdetection device of claim 1, wherein the drop detection device is aself-contained assembly or is molded into packaging for products.
 15. Adrop detection device comprising: a spherical inertia member disposedwithin an enclosure, the enclosure having a plurality of faces, eachface having a pressure contact member, wherein a predetermined amount offorce exerted by the spherical inertia member on one of the pressurecontact members causes a signal to be activated, wherein the signalactivates an alarm indicator in an electronic circuit, the electroniccircuit comprising: a battery having a first terminal and a secondterminal; a first resistor coupled to the first terminal of the battery;a fuse coupling in series the first resistor to the second terminal ofthe battery; a second resistor coupled to the first terminal of thebattery; an alarm indicator coupling in series the second resister to atransistor, and the transistor coupling in series the alarm indicator tothe second terminal of the battery; and a contact having a first contactend and a second contact end, the first contact end being coupled to thefirst terminal of the battery and the second contact end being coupledto the fuse, wherein if the contact remains open by keeping separate thefirst and second contact ends, then no current from the battery passesthrough the alarm indicator, and wherein if a pre-determined drop forceis exerted on the drop detection device, then the contact closes,resulting in the fuse being blown by current from the battery, such thatcurrent then flows through the alarm indicator.
 16. The drop detectiondevice of claim 15, wherein the alarm indicator is a Light EmittingDiode (LED).